Sunday, March 13, 2011

Smoke rising from the Fukushima Dai-ichi number one nuclear plant after a blast in Unit 1 on Friday

Exclusion zone widened to over 13 miles as radiation levels rise

Reactor 3 has lost its cooling system

Sea water being used to cool reactor

170,000 people evacuated from area near plant

Up to 160 people so far exposed to radiation

Japan's nuclear crisis was growing today amid the threat of multiple meltdowns, as more than 170,000 people were evacuated from the quake- and tsunami-savaged northeastern coast where police fear more than 10,000 people may have already died.

A partial meltdown was already likely under way at one nuclear reactor, a top official said, and operators were frantically trying to keep temperatures down at the power plant's other units as fears of a second explosion at the facility grew.

As the exclusion zone around the facility was widened to more than 13 miles today, Chief Cabinet Secretary Yukio Edano said that a hydrogen explosion could occur at Unit 3 of the Fukushima Dai-ichi nuclear complex, the reactor that could be melting down.

That would follow a blast the day before in the power plant's Unit 1, as operators attempted to prevent a meltdown by injecting sea water into it.

The damaged roof of reactor number 1 at the Fukushima Dai-ichi nuclear plant after an explosion that blew off the upper part of the structure

'At the risk of raising further public concern, we cannot rule out the possibility of an explosion,' Edano said. 'If there is an explosion, however, there would be no significant impact on human health.'

More than 170,000 people had been evacuated as a precaution, though Edano said the radioactivity released into the environment so far was so small it didn't pose any health threats.

A complete meltdown - the collapse of a power plant's systems and its ability to keep temperatures under control - could release uranium and dangerous contaminants into the environment and pose major, widespread health risks.

Up to 160 people, including 60 elderly patients and medical staff who had been waiting for evacuation in the nearby town of Futabe, and 100 others evacuating by bus, might have been exposed to radiation, said Ryo Miyake, a spokesman from Japan's nuclear agency.

Workers in protective clothing were scanning people arriving at evacuation centres for radioactive exposure. Three workers have so far been treated for radiation sickness after the explosion in the reactor building and locals have been offered iodine to help protect against radiation exposure.

Edano told reporters that a partial meltdown in Unit 3 of the Fukushima Dai-ichi power plant was 'highly possible'

Officials in protective gear check today for signs of radiation on children who are from the evacuation area near the nuclear plant

Asked whether a partial meltdown had occurred, Edano said that 'because it's inside the reactor, we cannot directly check it but we are taking measures on the assumption' that it had.

Japan struggled with the nuclear crisis as it tried to determine the scale of the Friday disasters, when an 8.9-magnitude earthquake, the most powerful in the country's recorded history, was followed by a tsunami that savaged its northeastern coast with breathtaking speed and power.

At least 1,000 people were killed - including some 200 bodies discovered today along the coast - and 678 were missing, according to officials, but police in one of the worst-hit areas estimated the toll there alone could eventually top 10,000.

People who are evacuated from a nursing home which is located in evacuation area around the plant rest at a temporary shelter in Koriyama today

The scale of the multiple disasters appeared to be outpacing the efforts of Japanese authorities to bring the situation under control more than two days after the initial quake.

Rescue teams were struggling to search hundreds of miles of devastated coastline, and thousands of hungry survivors huddled in darkened emergency centres cut off from rescuers and aid.

At least a million households had gone without water since the quake, and food and gasoline were quickly running out across the region. Large areas of the countryside were surrounded by water and unreachable. Some 2.5 million households were without electricity.

Police officers wearing respirators guide people evacuating the area around the plant

According to experts, any melted fuel would eat through the bottom of the reactor vessel. Next, it would eat through the floor of the already-damaged containment building. At that point, the uranium and dangerous byproducts would start escaping into the environment.

At some point in the process, the walls of the reactor vessel - 6 inches of stainless steel - would melt into a lava-like pile, slump into any remaining water on the floor, and potentially cause an explosion much bigger than the one caused by the hydrogen. Such an explosion would enhance the spread of radioactive contaminants.

If the reactor core became exposed to the external environment, officials would likely began pouring cement and sand over the entire facility, as was done at the 1986 Chernobyl nuclear accident in the Ukraine, Peter Bradford, a former commissioner of the U.S. Nuclear Regulatory Commission, said in a briefing for reporters.